The objective is to adapt Smart Cards as aids for individuals in adhering to therapeutic medical regimens. These microelectronic devices have a TMS series microprocessor with 64K bits of EEPROM (reprogrammable), a touch sensitive keypad, and an LC display. An internal battery supplies power that lasts for one year of daily intermittent operation. Specific aims are: (1) to adapt the devices for use in a weight control program, and (2) to test the use of these devices in an established weight control program at The IPM/The Methodist Hospital in Houston, Texas. Methodology includes: (1) program code development using aT.I./XDS Development System interfaced to a Smart Card emulation system, (2) on- and offloading data through external contacts in the devices (3) recording behavioral data and food records, and (4) comparing process variables and treatment outcomes of subjects enrolled in weight control programs who use the smart card devices and those who use conventional techniques. The potential for technological innovation exists in the adaption of a microprocessor with EEPROM for individuals where adherence with prescribed medical regimens is aided by self- reports of quantitative data in a small pocket-sized computer.